A NONMARINE VERTEBRATE COPROLITE ACME ZONE IN THE PERMO-TRIASSIC

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Lucas, S.G. and Zeigler, K.E., eds., 2005, The Nonmarine Permian, New Mexico Museum of Natural History and Science Bulletin No. 30.
INTRODUCTION
Häntzschel et al. (1968, fig. 3; Fig. 1) published the only statis-
tical analysis of the frequency of coprolites through time. This analysis
included both invertebrate and vertebrate coprolites from all environ-
ments and was based upon “statistical counting of the geologic age
assigned to the coprolite and faecal pellet specimens described in the
literature” (Häntzschel et al., 1968, p. 4). This figure shows a strong
correlation between frequency and age, with younger strata yielding
more coprolites. Häntzschel et al. (1968, p. 4) cautioned that this analysis
depended “widely upon the scientific advancements and activities of
geologists and paleontologists in the various countries of the world”
and “does not necessarily represent the actual distribution of coprolites
in geological time.”
Hunt et al. (1994, p. 2273-224) provided a brief qualitative re-
view of the distribution of vertebrate coprolites through the Phanero-
zoic. They noted, for example, that herbivore coprolites are rare prior
to the Quaternary. The purpose of this paper is to briefly discuss the
obvious abundance of vertebrate coprolites in the Permo-Triassic.
PHANEROZOIC RECORD OF NONMARINE VERTEBRATE
COPROLITES
Over the last 30 years, we have conducted extensive fieldwork
in nonmarine strata in North America, Europe and Asia ranging in age
from Carboniferous to Quaternary. It is this experience in addition to
our knowledge of museum collections that forms the basis of the fol-
lowing generalizations.
We have always been aware that “most paleontologists do not
collect vertebrate coprolites” (Hunt et al., 1994, p. 224). Vertebrate
coprolites are often the most common vertebrate trace fossils in non-
eolian environments (e.g., Hunt et al., 1998). However, this abundance
is not reflected in most paleontological collections, principally because
the majority of vertebrate paleontologists are principally interested in
body fossils (Hunt et al., 1994). Possibly the only major collection in
proportion to the number of vertebrate coprolites encountered by its
field collectors, is the New Mexico Museum of Natural History and
Science.
Our qualitative assessment of the distribution of nonmarine ver-
tebrate coprolites through the Phanerozoic suggests that pre-Permian
coprolites are uncommon. However, coprolites are abundant locally in
Permo-Triassic redbeds (e.g., Hunt and Lucas, 2005a, b). Later Meso-
zoic strata yield few coprolites. Coprolites are locally common in the
Tertiary (references in Hunt et al., 1994). Quaternary coprolites are
abundant, but only in certain depositional settings, notably caves (e.g.,
Buckland, 1823).
PERMO-TRIASSIC ACME FOR NONMARINE
VERTEBRATE COPROLITES
Early Permian-Late Triassic redbeds yield abundant vertebrate
coprolites— they have been reported from most significant outcrops of
strata of this age, e.g., North America (Neumayer, 1904; Hunt et al.,
1998), Europe (Augusta, 1936) and Asia (Jain, 1983; Ochev, 1974).
Vertebrate coprolites are not pervasive through all facies and are
only locally abundant (Hunt et al., 1988). The relative abundance of
different trace fossils is nonrandom and in need of further study. For
example, the Early Permian (principally Wolfcampian) redbeds of New
Mexico yield abundant tetrapod, and lesser numbers of invertebrate,
tracks and yet vertebrate coprolites are relatively uncommon. How-
ever, the reverse is true in the Early Permian (Wolfcampian-Leonardian)
redbeds of Texas. Notably, there are very large collections of vertebrate
trace fossils from both New Mexico and Texas, so sample bias is not a
significant factor in this disparity. Preliminary study of Late Triassic
coprolite distribution indicates that distinct coprofacies can be discrimi-
nated in the Chinle Group of western North America (Hunt et al., 1998).
A NONMARINE VERTEBRATE COPROLITE ACME ZONE IN THE PERMO-TRIASSIC
ADRIAN P. HUNT AND SPENCER G. LUCAS
New Mexico Museum of Natural History, 1801 Mountain Road NW, Albuquerque, NM 87104-1375
Abstract—Nonmarine vertebrate coprolites are uncommon in the pre-Permian, locally abundant in Permo-
Triassic redbeds, rare in the later Mesozoic strata, locally common in the Tertiary and common in certain
depositional settings (e. g., caves) in the Quaternary. There is thus a Permo-Triassic acme zone for vertebrate
coprolites in nonmarine environments.
FIGURE 1. Assessment of the distribution of coprolites through time by Häntzschel
et al. (1968, fig. 3).
Augusta, J., 1936, Ein Stegocephalian-Koprolith aus dem mährischen Perm:
Zentralblatt für Mineralogie, Geologie und Pälaontologie, Abheinlung B, 1936,
p. 334-337.
Buckland, W., 1823, Reliquiae diluvianae: London, 303 p.
Häntzschel, W., El-Baz, F. and Amstutz, G. C., 1968, Coprolites: An annotated
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